An LED panel is often mounted perpendicular to the horizontal plane, forming an LED display screen. The maximum-brightness view of the LED panel is on its normal direction, and its half-power angle is symmetric with respect to its normal direction. The half-power angle, also known as a power angle, is the angle measured from the normal direction at the center of a light source at which the luminous intensity drops to half the central luminous intensity I, namely I/2. When the luminous intensity of the light source is evenly distributed, the angles, offset from the normal, at which the surrounding luminous intensities become half the original luminous intensity, should be equal. When the luminous intensity is not even, the angles are not equal. An emitting angle of a diode is its light diffusing angle. In addition, a display screen may be mounted at a certain height so that people's view may be a low-angle view. Since one needs to look up to the screen, the visible range of the LED display screen may be narrowed. In order to satisfy the requirements of low-angle view, certain tooling or jigs may be utilized when LED plug-ins are installed to deflect the LEDs downward for a certain angle, so as to increase the lower half-power angle, namely, to increase the angle at which the light is deflected downward. However, this method requires a re-customized die for the LED display screen, with a relatively high manufacturing cost and mean versatility.